1. Field of the Invention
The present invention relates to a sensing system, and more particularly, to a sensing system having a reflective element.
2. Description of the Related Art
Touch systems have been disclosed in many patents, such as U.S. Pat. Nos. 4,782,328 and 6,803,906. Each of the touch systems disclosed in the above two patents must have at least two sensors such that the production cost of each of the touch systems disclosed in the patents is relatively high. One of the two patents is described thereinafter in detail.
FIG. 1 is a schematic view of a conventional touch screen system. Referring to FIG. 1, the touch screen system 100 disclosed in the U.S. Pat. No. 4,782,328 includes a panel 110, a first photosensor 120, a second photosensor 130 and a processor 140. The panel 110 has a touch screen area 112 which is a rectangle. The first photosensor 120 and the second photosensor 130 are disposed at two opposite ends of a boundary 112a of the touch screen area 112. The sensing range of the first photosensor 120 and that of the second photosensor 130 cover the whole touch screen area 112 respectively. Furthermore, the first photosensor 120 and the second photosensor 130 are electrically connected to the processor 140.
When a pointer 150 touches the touch screen area 112, the first photosensor 120 senses the pointer 150 along a first sensing path 162 and the second photosensor 130 senses the pointer 150 along a second sensing path 164. The processor 140 calculates the location of the pointer 150 according to the first sensing path 162 and the second sensing path 164.
However, the conventional touch screen system 100 must have the two photosensors 120 and 130 such that the production cost thereof is relatively high.